Here’s one way a teacher I know helps kids stay motivated with fluency. She’d got a bulletin board (not huge) with a star for every student. Each star has the student’s classroom number on it (not their name- for privacy reasons, and so she can use it the following year). All the start are laminated after she writes the number on it. About once or twice a month, she updates each kid’s star to show their current words per minute rate. She’s noticed that this really motivates some kids and it’s an easy way to show her class that fluency is important.
This idea could easily be adapted for home school kids. Laminate a shape and put it on your fridge. I guess there’s no real way to keep it anonymous, since your kids can probably figure out whose star is whose… But it’s still a good way to show that you as the parent value fluency.